It is apparently intended to enhance the idea of utter weariness, either because the word 'wearied' is in thought to be supplied, 'sat, being thus wearied, on the well'; or because it conveys the notion which might be expressed by our 'just as He was'; as a tired man flings Himself down anywhere and anyhow, without any kind of preparation beforehand, and not much caring where it is that he rests.